The proposed research will investigate relationships between gender and fertility motivation, as a first step toward a gendered theory of fertility. A major focus will be improved measurement of motivation strength. Category ratings, magnitude estimation techniques, and Item Response Theory models will be compared in terms of reliability, validity and gender bias. These analyses will identify high-quality, efficient measures of fertility motivation for periodic national telephone surveys, which are needed to improve fertility predictions. A panel of randomly selected Wisconsin residents age 18-34, married (nonparents and parents) or single nonparents, will be interviewed in two waves, one year apart. Spouses of married respondents will also be interviewed. A cross-sectional national survey of the same population will be conducted at approximately the same time as Wave 2 of the panel survey; spouses of married respondents will also be interviewed. Each survey will be conducted with a Computer-Assisted Telephone Interview (CATI) system. Measurement equivalence will be assessed for women and men parents and nonparents, single and married respondents. Gender equivalence will also be tested in couple models of motivation strength. Differences in the reliability or validity of category ratings, magnitude estimates, and IRT scales will be assessed. The relationship between strength of fertility motivation and fertility behaviors and outcomes will be examined with cross- sectional and panel data. Contraceptive use and, in the panel, occurrence of pregnancy, will be the behavior/outcome variables. For single respondents, involvement with a dating/sexual partner and, in the panel, marriage, are also relevant behaviors. For couples, models of agreement in goals and motivation strength will be specified to represent effects of homogamy, homophily, and mutual influence on agreement. Interaction models will be specified to determine the relative effects on couple behavior of (a) wife's motivation vs. husband's motivation: (b) pronatal vs. antinatal goals; and (c) the goals of the spouse with stronger fertility motivation.